Our aim is to analyze endocrine and other control mechanisms that regulate insect growth, and to examine the possibility of using hormonally active materials as safe insecticides to control pests and disease vectors. We have devised new approaches to insect endocrinology by using genetic mutants and techniques in the fruitfly Drosophila. One approach is to use segmental aneuploids to locate the structural genes for the enzymes involved in the synthesis and breakdown of several insect growth hormones, to produce mutations affecting these enzymes and analyze their effects on the phenotype. This combined use of genetics, biochemistry and insect physiology should permit a new kind of analysis of complex endocrine mechanisms. We also plan to analyze mutants we have selected which may have endocrine defects. We shall also analyze nonhormonal factors regulating insect growth. We have evidence that a key factor in regulating growth in different parts of an organ like an imaginal disc is the positional value of the cells, i.e. the information which cells have about their location in the organ. We shall investigate the mechanism whereby adjacent cells mutually regulate each others' growth rate. We are isolating and identifying the juvenile hormones of Thysanura. We are also interested in the use of insect hormone analogues, such as ecdysones and juvenile hormone analogues, as safe insecticides. In this connection we are examining the effects of insect hormones on the isopod crustacean, Armadillidium. In addition to gaining new insights into comparative endocrinology, we hope to learn how organisms besides insects may be affected by analogues of insect hormones.